random selection of different sequences of primes within one block

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random selection of different sequences of primes within one block

random selection of different sequences of primes within one block

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juliane_d	juliane_d posted 11 Years Ago Topic Details Share Topic
Group: Forum Members Posts: 12, Visits: 39	Hi there, I am programming an experiment in which two different sequences of trials are presented within one block in random order (and different frequencies). Instead of this: /trials = [1-16 = sequence(fixtrial1, primetrial); 17-24 = sequence(fixtrial2, detection) which presents the first sequence of 2 trials 16 times and the second 8 times afterwards, I would like to actually do something like this: /trials = [1-24 = random(sequence(fixtrial1, primetrial), sequence(fixtrial1, primetrial), sequence(fixtrial2, detection); which obviously does not work. Meaning that 2/3 of trial sequences within the block should be sequence(fixtrial1, primetrial); randomly interspersed by 1/3 of the sequence (fixtrial2, detection). Is there an easy way to do this? As always, any help would be much appreciated! thanks, Juliane
	Reply Like 27
Dave	Dave posted 11 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 13K, Visits: 108K	> Is there an easy way to do this? Yes, several actually. The easiest in your case: - /branch from <trial fixtrial1> to <trial primetrial> - /branch from <trial fixtrial2> to <trial detection> - sample only the fixtrials (1,2) at the <block> level in the desired proportions <trial fixtrial1> [...] / branch = [trial.primetrial] </trials> <trial fixtrial2> [...] / branch = [trial.detection] </trials> <block someblock> / trials = [1-24=noreplace(fixtrial1, fixtrial1, fixtrial2)] [...] </block>
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juliane_d	juliane_d posted 11 Years Ago ANSWER Post Details Share Post
Group: Forum Members Posts: 12, Visits: 39	Hi Dave Thanks for the quick and super helpful response. It works just fine! Cheers, Juliane
	Reply Like 24